In many industries, X-ray sources or neutron sources may provide useful information about the quality or nature of a material or object. For example, large, high-powered technologies such as linear accelerators, synchrotrons, and free-electron lasers are often used to produce X-rays in scientific research. Likewise, nuclear reactors, fusors, and gas discharge tubes have been used as neutron sources in nuclear activation analyses. Each of the above-mentioned technologies is large and consumes a significant amount of power. Accordingly, the information gathering capabilities of X-ray and neutron sources is unavailable for use in confined spaces and in more remote locations. Efficient particle emitters have other applications, including without limitation, use in ion propulsion.